CAIRO — President Abdel Fattah el-Sisi of Egypt sought on Wednesday to reassure residents of Sharm el Sheikh about the exodus of tourists after the crash of a Russian charter jet after takeoff from the resort’s airport. But to Egyptians worried about putting food on their tables, he offered little comfort.

“Be like this!” he urged, holding up a fist. “We won’t eat? Fine, let us not eat! We will be hungry? So what? Let us be hungry!” he said in a television interview at the Sharm el Sheikh airport. “Do you think that anyone can defeat the Egyptians?”

Two weeks after the crash, most of the world has concluded it was most likely a bombing, and several countries, including Britain and Russia, have canceled flights to the resort area.

Satellite images, flight data recorders and the scattered debris show that the plane exploded suddenly in midair. The Egyptian branch of the Islamic State, also known as ISIS or ISIL, has claimed responsibility. Western governments have said intelligence intercepts lend some credence to the claim. And Egypt has disclosed no clues pointing to any alternative explanation — nor much information of any kind about the investigation.

Instead, Mr. Sisi and his supporters have shut down any discussion of possible terrorism, and rallied patriotic passions against the idea, portraying Western alarms as a plot against Egypt.

“Of course we are talking about a conspiracy,” Dr. Alaa Abdel Wahab, an adviser to the minister of tourism, said Thursday in a telephone call to a morning talk show. Dr. Wahab argued that Western governments were trying to harm Egypt because they resented “the popular support for President Sisi.”

Egyptian officials have invoked similar themes for decades in response to crises, from Egypt’s defeat in the Arab-Israeli War in 1967, blamed on the United States and Britain, to the deadly floods this fall in Alexandria, blamed on the plugging of sewers in the city by Islamists.

But with so many jobs at stake — and so many other countries watching the investigation — some say the government’s response to the crash may be testing the limits of Egyptians’ willingness to suspend their criticism and to unite against an ambiguous foreign threat.

After Mr. Sisi’s bellicose talk of going without food, “people are just making fun of him,” said Hisham Kassem, a veteran Egyptian journalist sympathetic to the president. “I am disappointed.”

The government has approached every crisis as a shadow war against foreign enemies, Mr. Kassem said, perhaps reflecting Mr. Sisi’s years in military intelligence before he led the ouster of President Mohamed Morsi of the Muslim Brotherhood two years ago. “The president and all of his advisers are from the security services,” Mr. Kassem said, but “if you are going to handle a P.R. crisis using the security services, you are going to bungle.”

International protocol gives Egypt leadership of the multinational crash investigation, and the government has sought to keep a lid on information, arguing that theories about the cause are premature. But the rest of the government’s communications appear to all but deny any conclusion of terrorism. Admitting to a bomb now could appear to be a humiliating reversal.

“Thinly veiled ill will has permeated the premature speculation of Western powers,” Galal al-Nassar, the editor in chief of the state-run Al Ahram Weekly, wrote in an editorial titled “Intentional Defamation,” which was republished on a Foreign Ministry website.

The discussion of a possible bombing was “a systematic campaign by the U.K. and U.S. media against Egypt,” Mr. Nassar wrote. “The loss of life in Sinai is just an excuse to put Egypt in its place and punish it for ousting the Muslim Brotherhood.”

Video

As bodies from the Russian airliner that crashed in the Sinai Peninsula on Saturday arrived in Cairo, officials in Egypt and Russia discussed the investigation.Published OnOct. 31, 2015CreditImage by Mohammed Hossam/European Pressphoto Agency

Such Egyptian coverage of the crash is “absurd” and “disconnected from reality,” said Samer Shehata, an Egyptian-American political scientist at the University of Oklahoma. “It just shows how really troubling it would be to address the issues head on: that there is a militant insurgency in Sinai, that the army has not been able to defeat it, and moreover, the insurgents have now managed to penetrate a part of the government — in the Sharm el Sheikh airport.”

Rallying against conspiracies is a time-tested strategy in Egypt and other authoritarian states, historians say.

“The conspiratorial line increases the sense of alarm among people and prevents them from thinking critically, because conspiracies by their nature are hidden and mysterious,” said Khaled Fahmy, an Egyptian historian now teaching at Harvard.

Pro-government voices now dominate the Egyptian news media and often argue that the turmoil that has followed the Arab uprisings of 2011 is part of a grand Western plot, Dr. Fahmy said. (The Islamic State is routinely attributed to an American conspiracy.) “Every smaller crisis is cast under the larger conspiratorial mind-set,” he said, “to convey that the government is in charge and the people have to rally in a unified way behind its leadership.”

Egyptian officials have felt little pressure to publicly account for previous disasters. After a military airstrike in September mistakenly hit a picnic of Mexican tourists, killing a dozen people, the government promised an internal investigation, but prosecutors promptly issued an order barring the news media from discussing the airstrike. Nothing more has emerged.

The next month, days of heavy flooding in the streets of Alexandria killed at least seven people. Many Egyptians were upset by the government’s feeble response to the floods, and in a rare example of public accountability, Mr. Sisi accepted the resignation of the provincial governor, Hani el-Mesery. (Residents of Sharm el Sheikh, where lax airport security is suspected by Western governments of playing a role in the crash of the Russian jet, say Gen. Khaled Fouda, the governor of their province, may have more job security: His son married Mr. Sisi’s daughter last year, according to news reports. Spokesmen for the president and the governor did not respond to requests for comment.)

But then, as the floods and deaths continued, the Egyptian police announced that they had uncovered a conspiracy behind the crisis: Seventeen members of the Muslim Brotherhood — which the Sisi government has outlawed as a terrorist group — had plotted to plug the sewers. Egyptian television networks broadcast an Interior Ministry-produced video of confessions by dazed-looking young men, and the alleged culprits demonstrating for the cameras how they had clogged the sewers.

Many rolled their eyes at the idea, and some news reports said the suspects had been arrested before the floods.

With promises of public security and an economic recovery put off, small cracks have begun to appear in the president’s previously wall-to-wall support from the Egyptian news media.

During parliamentary elections, one pro-government talk show stunned viewers by broadcasting a call from a woman who said her disappointment with Mr. Sisi had kept her from the polls. She cited a much-hyped economic conference hosted by the president that failed to bolster growth, and an expansion project billed as a “new” Suez Canal, which had resulted in a decline in toll revenue. “I am sorry, but we are kidding ourselves,” she said. “I feel cheated.”

This month, Azza el-Hennawy, a state television newscaster, broke from her script to rail against bribery and self-dealing that she said had weakened the government.

“Look at the corruption in the local councils and think about holding officials accountable — starting with you, Mr. President, because you are the one who appoints them,” she said. “What are you responsible for? Where is your plan? Where is your vision?” (She was suspended from her job, pending an investigation by her network.)

And this past week, Lamees el-Hadidi, one of the most popular pro-government talk show hosts, said in a broadcast that the government was compounding the economic pain from the plane crash by scaring away investors with the detentions of a prominent investigative journalist, Hossam Bahgat, and a newspaper owner, Salah Diab.

“If I am now in a very difficult situation with tourism and a foreign plot, do I need to make another problem with investments and another problem with freedoms?” she asked. “We don’t need a foreign conspiracy. We are the conspiracy itself. We conspire against ourselves!”